An Obstetrician-Gynecologist (OBGYN) is a doctor who specializes in everything related to women’s reproductive health, including pregnancy and childbirth. OBGYNs screen for certain diseases such as breast cancer and cervical cancer. They also diagnose and treat women’s reproductive health issues including sexually transmitted infections (STIs), menstrual issues, abnormal bleeding, polycystic ovarian syndrome, fertility, and more. Some OBGYNs specialize in maternal-fetal medicine, which means they treat and monitor pregnant women and their babies. They also perform deliveries and c-sections.